Episode starts out with Bulkhead and Sumdac working together to try and build a new space bridge. They have some disagreements, like where to put it, and we see it cave in the roof of Sumdac Tower, leaving a pile of rubble a few floors deep. Bulkhead goes to find Mix and Scrapper to help clean it up (them being construction and all). While this is happening, Prime and the others are duking it out with Lugnut. Bulkhead finds Mix & Scrapper doing one of the things they do best, eyein cars as they go by, and brings em back to help with the cleanup. It almost looks like the two cons are having a change of heart when Scrapper tries to pull up a heavy load, once it reaches the top, we see that the rubble originally contained a headmaster unit and something Decepticon, which, I think coupled with an Alspark fragment, makes a new, shorter then Bee Decepticon, Dirt Boss. DB looses no time in asserting his control over the two cons, even making use of what looks like a Cerebro Shell. Sumdac walks in on the four, and to avoid him getting hurt, Bulkhead makes DB and the cons believe he's Sumdac's boss.
DB ends up coming up with a plan to hijack building materials and oil, and using it to punish the humans, much to the dismay of Mix & Scrapper. We see more of the Autobot/Lugnut battle, with the team having to use two stasis cuffs, linked to shut the big lug down. Unfortunatly, he and Prime are now stuck at the bottom of a giant crater. Bulkhead finally has enough, and tries to stop DB & the gang before they blow up a small oil tanker. He gets hit by one of the CS and is somewhat forced to help them. Prime & the others leave Lugnut, figuring that he can't go anywhere, and go to help Bulky. Fight ensues, Ratchet uses his magnets to remove the shell, and in the ensuing battle, a spark of flame is struck leading to the tanker being set aflame anyways. Before it can explode however, Bulkhead reprograms one of the wave generator things (seen from last episode warping OS, Megatron, and Screamer) to warp the tanker, DB, & the cons, someplace safe. They appear near Dinobot Island (in the sea, but we see the tanker drop in from DBI) and it explodes. Prime & the others make it back to where they left Lugnut only to find him gone and with no trace, and we find that he was saved by Ramjet, who "promises not to tell Megatron"

. Good episode none the less, but really liked the idea that it could have been about Blitzwing, even though we never see him in the episode. Couple of small items I forgot to include, Sumdac has undone the dampners he put on the Cons last season, so they're not so invisible now. Also, Sari is not shown in the entire episode. Hope this helps.